Motorcycle Roadworthy and Modifications Frame and Suspension Alterations

Important Information Regarding Frame and Suspension Alterations on Motorcycles

At Ausmec Mobile RWC and Mechanics, we strongly recommend following the Queensland Department of Transport and Main Roads (TMR) guidelines ( when considering modifications to your motorcycle's frame or suspension.

These components are crucial for safe handling and stability. Altering them can significantly impact your motorcycle's performance and potentially put you and other road users at risk. The TMR outlines specific regulations for modifications such as:

  • Custom frames: While properly designed custom frames can be acceptable, they require an engineer's report for approval.
  • Extended forks: Extending your motorcycle's forks can affect handling and braking. Approval is needed for such modifications.
  • Hard tail conversions: Converting a suspension system to a rigid "hard tail" setup requires TMR approval.
  • Mono-shock conversions: Replacing the traditional dual shock absorbers with a single mono-shock system necessitates TMR approval.
  • Structural modifications: Any structural changes to the frame or chassis require an engineer's report and TMR approval.

Engineer's Report and TMR Approval Process:

If you're considering any of the modifications mentioned above, you'll need to engage the services of an Approved Person Engineer with the LO1 code before starting the work. These engineers are qualified to assess the modifications and provide a report for submission to the TMR for approval. You can find a list of Approved Person Engineers in your area on the TMR website (

Safety First:

At Ausmec Mobile RWC and Mechanics, your safety is our priority. We recommend consulting with a qualified mechanic or engineer before undertaking any modifications to your motorcycle's frame or suspension. Following the TMR guidelines ensures your motorcycle remains safe and roadworthy for a confident and enjoyable ride.

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